Detection of Listeria monocytogenes based on combined aptamers magnetic capture and loop-mediated isothermal amplification

Rapid detection of Listeria monocytogenes (L. monocytogenes) is important to ensure timely treatment and to prevent outbreaks of listeriosis. Here, we reported an efficient and accurate system using aptamers magnetic capture and loop -mediated isothermal amplification (AMC-LAMP) for sensitive detection of L monocytogenes. A set of combined aptamers (including four individual aptamers with high binding affinity to L. monocytogenes) was conjugated to magnetic beads, used for capture L. monocytogenes. After incubation at room temperature for 45 min, the captured L monocytogenes cells were directly used for DNA extraction (1 h). Subsequently, the LAMP assays were carried out at 63 degrees C for 40 min, and the amplification products were visualized via SYBR Green I staining. The AMC-LAMP had a detection limit of 5 CPU/mL, and the total assay time was approximate 3 h. By the protocols developed in this study, 17 food samples was test for L. monocytogenes without prior culture enrichment. The accuracy of AMC-LAMP was shown to be 100% when compared with culture-biotechnical examination, while PCR failed to detect L. monocytogenes in one of five positive samples. These results indicate the developed AMC LAMP is a potential useful method for rapid screening and on-site detection of L monocytogenes in food samples. (C) 2017 Elsevier Ltd. All rights reserved.